- Extremely Hard Sudoku: 300 Very Difficult Sudoku Puzzles with Solutions: Volume 21
- Adult Coloring Book of Bizarre and Wonderful Creatures: Animal Human Hybrids, Four-Legged Birds, Sea Monsters, Two Faced Livestock, Odd Mutations, and More!
- Extremely Hard Sudoku: 300 Very Difficult Sudoku Puzzles with Solutions: Volume 25
- Extremely Hard Sudoku: 300 Very Difficult Sudoku Puzzles with Solutions: Volume 13
- Extremely Hard Sudoku: 300 Very Difficult Sudoku Puzzles with Solutions: Volume 11





























